An aircraft having an air cushion system is desirable for all-surface traversing. Also, an aircraft that can traverse all-surface types is desirable to have short takeoff and landing capability. Aircraft utilizing the ground effect or air cushion effect for lift are known in the art. For example, U.S. Pat. No. 4,298,175 discloses an airplane having an inflatable type air cushion confining undercarriage thereunder wherein the airplane wing structure comprise three-dimensionally enlarged inner wing components merging aerodynamically with the airplane fuselage. However, the transition from the aircraft being supported aerodynamically by the air cushion to being supported aerodynamically by the wing is the most critical segment of flight. The aforementioned patent and does not address this problem.
During the start of the takeoff roll the vehicle is totally supported by the air cushion. Once takeoff speed is reached and the aircraft is rotated to a takeoff Angle of Attack (AOA) the back of the cushion may be pressed down and contact the ground or the front of the cushion may rise up causing it to leak and loose effectiveness. This causes the vehicle to sink back to the ground and the AOA to decrease and at worst may develop into dangerous pitching oscillations. At best, the take off ground roll will be increased compared to a conventional geared aircraft, because additional airflow, and thus additional groundspeed and ground roll will be required to allow the wing sufficient lift to transition from air cushion lift to wing lift.
The following Patents relating to wing designs are also considered relevant background to the present invention, and are expressly incorporated herein by reference: Shirk, U.S. Pat. No. 4,415,132, issued November, 1983; Cornelius, U.S. Pat. No. 1,865,744, issued July, 1932; Leidy et al. U.S. Pat. No. 3,870,253, issued March 1975; Cornelius, U.S. Pat. No. 2,406,588, issued May 1944; and Lippisch, U.S. Pat. No. 3,627,235, issued December 1971.
The following Patents relating to ground effect designs are also considered relevant background to the present invention, and are expressly incorporated herein by reference: Berezhnoi, et al., U.S. Pat. No. 3,981,462, issued September 1976; Earl et al., U.S. Pat. No. 3,275,270, issued September 1966; Dornier, U.S. Pat. No. 3,082,976, issued March 1963; Creasey et al., U.S. Pat. No. 3,117,747, issued January 1964; Cockerell, U.S. Pat. No. 3,124,322, issued March 1964, Nowak; U.S. Pat. No. 2,483,663, issued October, 1949; Le Bel, U.S. Pat. No. 2,989,269, issued June 1961; Dornier, U.S. Pat. No. 3,070,327, issued December 1962; Lee, U.S. Pat. No. 3,297,280, issued January 1967; Todd, U.S. Pat. No. 3,458,007, issued July 1969; and Parkhouse, U.S. Pat. No. 3,561,558, issued February, 1971.
Murphy, published U.S. Patent Application, Publication No. 2006/0009093, published Jan. 12, 2006 and incorporated herein by reference, discloses a boat using a wing to vary lift between the hull and trims with an elevator. As the Murphy application was published after Applicant's effective Provisional filing date, it is unclear whether Murphy qualifies as “Prior Art” to applicant's invention, but is included here for completeness.